Learn How a Sewer Dye Test Can Be Used to Discover Leaks or Pipe Defects

Opinion & Expertise, Sewer Line Replacement
February 12, 2020

by David Balkan

Sewer Dye Test Fluid

Do you know how to perform a residential sewer dye test to discover leaks? Municipalities will conduct a sewer dye test to determine if freshwater and storm water run-off are entering the city’s sanitary sewer lines. This is one of the main reasons why raw sewage overflows into creeks and neighborhood drainage systems. The two lines – sewage and storm water drainage are purposely separated to prevent this from happening. Municipalities also conduct investigations to see if sewer leaks are causing roadway washouts, or other defects. There are of course other types of water leak testing, to learn more read this leak testing guide.

Tube of green dye

Residential Sewer Dye Testing

If you are a homeowner, you can also face the same problem of water leaking from an unknown source. That’s when a sewer dye test can be performed by a plumber. Such a test can determine if your home’s yard drainage system is properly connected, or defective. You may have a combined public sewer main fronting your property. A combined sewer is sized to take both waste water from home, as well as rain water from your roof leaders, etc. On the other hand, a separate dedicated sanitary sewer only accepts blackwater from toilets, and greywater. Most people are not familiar with the terms “blackwater” or ”greywater”. Greywater is considered waste water from your home’s drains, sinks, washing machines, dishwashers, and bathtubs. In simple terms, it is wastewater other than from toilets that does not contain fecal matter. In some jurisdictions it is reused for other purposes, such as flushing a toilet. This reuse acts to help preserve our precious resource of fresh potable water. Blackwater on the other hand cannot be reused until it is properly processed at a sewage treatment plant. Blackwater contains human waste, or other items heavy in bacteria and potentially harmful components.

The 4 Primary times when you need to perform a sewer dye test

  1. A problem with pooling water around the home’s foundation or low spots
  2. To verify that your property drains into the proper public sewer system
  3. Any water flowing either above ground or onto a basement floor
  4. If a roadway or sidewalk washout exists, yet there is no fresh water leak present
Toilets can be easily used to insert dye

Performing an Investigation For a Residential Sewer Leak

A home sewer dye test itself is not complicated to perform. However, when performed by a professional plumber, they can not only conduct the dye test but also accurately determine what the result may indicate. If dye becomes visible to the eye, then your home has failed the dye test. You will then need a licensed plumber in the area who can make the necessary repairs. This may mean one of two things. You may need a plumber to properly connect your home’s drainage system to the proper public sewer system. This would legalize improper existing sewer connections. In the second case, loose or disconnected drain pipes would have to be repaired. This would alleviate the leakage of waste water, and the problems that this causes.

The 7 steps to perform a sewer investigation to check for pipe defects

The following will verify that all sanitary sewer drains are properly plumbed. It will also make sure there are no cross-connections to the storm drain system. Here are the simple 7 steps to perform a residential sewer dye test:

1. What type of dye to use for the test

In the past, your best option was to purchase an appropriate liquid sewer tracing dye. You had to make sure that it was non-toxic, non-staining, and biodegradable. The goal is to force the brightly colored dye into the system, then watch where the dye exits. As secondary choices you could have used food dye, or clothing dye. If none of these items are readily available, and the leak seems close, you could even use milk. If you use milk and have a sewer leak, the leaking water will turn milky white.The best available and easiest to use dye option now comes in the form of tablets. Because these dye tablets are highly concentrated, wear rubber gloves. Simply insert one single dye tablet into your plumbing system. Using tablets avoids the risk of spills, stains, or ruining personal possessions.

Sewer Dye Tablets are convenient and easy to use

2. At what point do you start the test?

Locate the discharge points of the sanitary sewer and the storm drain piping around the home. Locations where you suspect unwanted leakage are good candidates. If your issue is outside the home, find the nearest exterior sanitary sewer outlet near the home. This is typically your main house trap. If these locations pose a challenge, simply flush the dye down inside your toilet (see below).

3. How to insert the dye for a sewer dye test

Pour the dye inside the toilet bowl or into an under sink drain trap. Start flushing the toilet several times, or run the water into the sink for several minutes.

4. The waiting period for a determination

Depending on where the leak or cross-contamination exists, you may have to wait minutes or hours before seeing the dye flow through your home’s plumbing system. The dye can appear in floor drains/covers, sump lids, or onto the flooded basement or yard areas.

5. What if no colored dye appears?

If no dye appears – then you can assume your drainage and sewer systems are properly connected, and you may simply have a water line leak somewhere with your home.

6. The confirmation that you have a sewer drain issue

If you do observe dye flowing into unwanted areas, then you will need the services of a plumber to make the right repairs inside your home.

7. The worst case scenario

In worst case scenarios, the sewer dye test will show dye appearing inside a public sewer not meant for that type of waste water flow. To know this, manholes on the public sewers will have to be lifted. This task is best left to a professional. These are sewer repairs that are the most expensive. It will entail rerouting that particular waste water to the correct public sewer in the roadway. Storm sewer can only accept storm water, sanitary sewers can only accept  sanitary waste water. Only combined public sewers can accept both sanitary waste water and storm water.

Tips for Liquid or Tablet Form Trace Dye Testing

Tip 1 – If possible, have the home’s plumbing diagrams on hand to mark where the dye is added. Also carefully note where the dye exited. Also, record what time the dye was added and what time the dye was seen leaving the system. The length of time indicates how far away from the insertion point the defect is. All of this information will be of value to your plumber in diagnosing the extent of your plumbing problem.

Tip 2 – For best results, follow the dye manufacturer’s instructions or add about a tablespoon of dye to each home fixture. If you are using dye in a tablet form just insert 1 tablet. Plumbing fixtures include the toilet, floor drains, sinks, and any fixtures that are plumbed to the sanitary sewer system.

Tip 3 – It is best to flush each fixture with over 10 gallons of water, or at least until dye is observed leaving the sewage system. The more water you flush, the less time it will take to observe the dye exit the system.

Tip 4 – You may station people at multiple sites at each sanitary and storm drain discharge point until the dye is observed. Once dye is observed, note the time, and repeat steps dye flush test for each drain that you suspect may be leaking.

Tip 5Contact Balkan Sewer and Water Main, the largest and most trusted sewer and water main service NYC for help with your next sewer dye test. Count on Balkan for fast, courteous service and quality work from experienced crews, including sewer replacement services for residential and commercial businesses.

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David Balkan

David Balkan is the CEO of Balkan Sewer And Water Main, the largest and most trusted service in New York City. David is extremely active in various NYC plumber organizations being the Chairman of the Subsurface Committee in the Master Plumbers Council, and Vice President of the Subsurface Plumbers Association. In addition David’s expertise is respected by officials of New York City agencies such as the NYC DEP, NYC DOB, and the NYC DOT. He frequently provides valuable input on a variety of industry related matters.

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